The 14th Amendment says if you were involved in an insurrection you can't be president. SCOTUS said they won't allow anyone to enforce that because of reasons they made up.
The Constitution doesn't say the president is immune from criminal law. SCOTUS decided he is because of reasons they made up.
So according to SCOTUS a sitting president can do anything and also there are 2 months between election and inauguration, which presents a sort of one man purge situation
